title: T cell differentiation and cytokine expression in late life.
abstract: Elderly humans are at significant risk with regard to the incidence and severity of many infectious diseases and cancers. Current theory holds that these late-life vulnerabilities arise, in part, through age-related changes in immune function, particularly in the T lymphocyte lineage. Herein, we discuss how such factors as thymic involution and ongoing T cell differentiation in the peripheral tissues contribute to progressive and irreversible shifts in the state of differentiation of the mature T cell pool. We propose that, by late life, these processes yield a T cell compartment with a suboptimal balance of naive and memory T cell subsets, each with altered, subset-specific programs for cytokine gene expression. As such, the T cell compartment in late life may be more prone to immune deficiency or cytokine-mediated dysregulation in response to new or previously encountered pathogens.
authors.affiliation: Department of Epidemiology, University of Michigan, Ann Arbor 48109-2029, USA. mhobbs@sph.umich.edu
authors.forename: M V
authors.initials: MV
authors.lastname: Hobbs
authors.forename: D N
authors.initials: DN
authors.lastname: Ernst
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000276:immunology*; D000818:Animals; D002454:Cell Differentiation; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000145:classification / Q000166:cytology* / Q000276:immunology*
chemical_list: D016207:Cytokines